Hiya,
Upon further investigation it would seem that all the books I had as epubs aren't registering as epubs anymore. I tried to convert them again and got the dreaded "not a valid sorce format" error.
I'm going to try and convert them to something else once the current job is done.
For the record it's the most recent version and I did try uninstalling and reinstalling.
Thanks for the help
Melly